In the LTE (Long Term Evolution) system provided in the 3GPP (3rd Generation Partnership Project), it has been proposed to apply Synchronous Hybrid Automatic Repeat Request (NPL 1). As illustrated in FIG. 1, when an uplink PUSCH (Physical Uplink Shared Channel) signal is first transmission, transmission acknowledgement information (ACK/NAC) is transmitted by the PHICH (Physical Hybrid Automatic Repeat Request Indicator Channel). When a mobile terminal apparatus receives NAC in the PHICH, the uplink PUSCH signal is retransmitted at predetermined intervals (RTD: Round Trip Delay, 8 msec) (Non-adaptive retransmission). In this case, the mobile terminal apparatus retransmits the PUSCH signal in the same resource (RB: Resource Block).
In the meantime, in the LTE system, when the PUSCH signal is retransmitted in the same RB by Non-adaptive retransmission, it may interfere with another UE signal (for example, PRACH (Physical Random Access Channel) signal). Accordingly, as illustrated in FIG. 1, it is also proposed to retransmit the PUSCH signal in a different RB in retransmission (adaptive retransmission). In this case, the mobile terminal apparatus receives RB allocation information used for retransmission in the downlink control channel (UL grant of PDCCH (Physical Downlink Control Channel)).
Further in the LTE system, in order to achieve much faster transmission, the MIMO transmission using plural transmission/reception antennas is adopted in the radio base station apparatus. Further, in the LTE-Advanced (LTE-A) system, which aims to achieve a more broader band and a more faster transmission rate, the MIMO multiplexing transmission is performed of a maximum of 8 streams in the downlink and a maximum of 4 streams in the uplink. In the MIMO multiplexing transmission, multi codeword transmission is performed which is capable of different MCS (Modulation and Coding Scheme) controls and HARQ controls among streams. Here, the maximum number of codewords is 2 irrespective of the number of antennas.